Research On Network-Coding-Based Energy-Efficient Technology In Wireless Sensor Networks

In recent years, the advancement of new technology and decreament of the cost of manufactory accelate the development of Wireless Sensor Networks (WSNs). Since the sensor nodes are easy to be deployed and have various functions, they are widely used in different fields such as medicalcare, target tracking, environment mornitoring and so on. The main task of sensor nodes is to collect data, store data, and transmit the data to a sink node for further processing and operation. The limitation of sensor nodes and unreliability make the designment of efficient communication, storage mechanism become significant challenges.Routing technology is an important supporting technology of WSNs, the performance of routing protocol has a significant influence on the quality of networking. Because there are many differences in the feature of network, feature of business and application requirement between WSNs and traditional networks, the routing design of WSNs faces a series of new challenges. This dissertation addressed reliable data transmssion technology, data storage technology and multicast technology with high energy efficiency.(1) In this dissertation, we studied the energy efficiency of network-coding-based multipath routing technology for WSNs. The employed multipath network model is the braided routing model, and the employed network coding scheme is the random linear network coding. Moreover, we studied the Successful Delivery Ratio (SDR) and Energy Comsumption (EC) of the network-coding-based multipath routing technology.(2) We analyzed the influence of different parameters such as the number of hops, the length of packets, the size of sub-packet, the size of cluster and so on. Based on these results, an optimal scheme is achieved, which makes the network accomplish network transmission with less resource. Moreover, through extensive simulations of discrete events, we observed that the results of simulations are consistent to that of analysis. Some evaluations on extreme environment (such as congested networks and failed nodes) are carried, which shows that the proposed scheme is robust to these environment.(3) We proposed an energy-efficient distributed storage and repair scheme. Through constructing sparse generator matrix, we achieved a scheme to implement energy-efficient storage scheme. In addition, the idea that re-encoding at intermediate nodes from network coding theory is employed to design an iterative repair scheme, which significantly reduces the required transmission time, and hence making the repair in Wireless Multi-hop Networks much efficient. Through theorectical analysis, we proved that the employed scheme could work over a very small finite field, which implies that the computation overhead would be low. Finally, through extensive experiments, we showed the scheme could reduce the total energy consumption, and in the mean time, the energy consumption is highly balanced. Therefore, the lifetime of the network is increased.(4) We introduced the multi-rate network coding into the communication of Wireless Multi-hop Networks, which could increase the throughput of multicast networks. And we proposed a multi-rate network codes construction method. By using this method, the receivers could receive at their individual max-flows in many practical applications. Moreover, we provided a method, called Flow-Alignment, to separate independent routes from the topologies, which could ruduce the computation complexity of multi-rate network codes.(5) We provided a sufficient condition to judge whether the transmssion scheme that makes all the receivers receive at individual max-flow exists. When the condition is satisfied, the goal can be achieved. Through extensive experiments, we observed that the proposed coding scheme could increase the throughput of network, reduce the energy consumption of data transmission, and guarantee the decodabiltiy of receivers.